Electrical contact members.



H. v. 8. TAYLOR.

ELECTRICAL CONTACT MEMBERS.

APPLICATION FILED JAN-21,1916.

l a pawu Patented July 10, 191?.

WITNESSES: INVENTOR Horace 5/ 1f E y/0;?

. ATTORNEY urrnn earns PTEN union,

HORACE V. S. TAYLOR, 0F PITTSBURGH, PENNSYLVANIA, ASSIGNOR TOWESTINGHOUSE ELECTRIC AND MANUFACTURING COMPANY, A CORPORATION OFPENNSYLVANIA.

' nnnc'rnrcan con'raor MEMBERS.

Specification of Letters Patent.

Patented. July MP, 1191?.

Application filed January 21, 1916. erlal K0. reset.

T 0 aZZ whom it may concern:

Be it known that 1, Homes V. S. TAYLOR, a citizen of the United States,and a resident of Pittsburgh, in the county of Allet gheny and State ofPennsylvania, have invented a new and useful Improvement in ElectricalContact Members, of which the following is a specification.

My invention relates to contact members 1% lators, switches and similarapparatus and it has for its object to provide a pair of cooperatingcontact members that shall be comparatively inexpensive, durable, notsubject to pitting or burning and consequent roughening during operationor to sticking or fusing together, and the surfaces of which shallremain clean and free from oxid or other insulating coatings or films,insuring the at making of good contact when the members are brought intoengagement;

Many attempts have heretofore been made to provide a suitableinexpensive substitute for platinum and iridium for the engaging vices,tungsten and molybdenum, among other materials, having been proposedbecause of their high fusing points. Howso ever, tungsten and molybdenumare readily oxidizable and their oxids are non-conductors. Consequently,when both members are composed of tungsten or molybdenum, a film of oxidforms upon the member conas stituting the anode and prevents, orinterferes with the making of reliable and eifective electrical contactbetween the members. It has also been proposed to employ silver for bothof the contact members, but it has been found that, when such membersare subjected to severe service, the member constituting the cathode isapt to pit badly and to become rough because of the relatively lowfusing point of silver.

According to my invention, which is illustrated in the single figure ofthe accompanying drawing, the anode 1 is composed of silver, platinum oriridium, or some other precious or noble metal that does not oxidizereadily or the oxid of which is a reasonably good conductor,' and thecathode 2 is composed of tungsten or molybdenum or some other metal thathas a high fusing that are adapted for use in relays, regufaces of themake-and-break contact mem- 'bers of relays, regulators and slmllardeium is used for both contact members.

point. If silver is employed as the anode in th s arrangement, thetendenc to form an oxid film upon the silver is of ut little consequencefor the reason that the oxid is a reasonably good conductor, and ifplatinum 'or iridium is employed, the anode surface does not readilyoxidize. Where the service to which the contact members is subjected isnot extremely severe silver is referably employed for the anode surfaceecause it is less expensive than platinum and iridium, but for the mostsevere service, platinum or iridium is preferably employed. he cathodedoes notrpit or burn easily because of the very hi 'h fusing point oftungsten, and it, there ore, remains clean and smooth.

The members also do not become fused or stuck together because thefusing points of tungsten and molybdenum are above those of the othermetals which volatilize and disappear, if the temperature becomesexcessive, before the former metals reach the fusing, point. This isespecially true of the combination of silver and tungsten.

The combination herein set forth has been found very effective andreliable and much less expensive than when platinum or irid- The contactresistance is low and the contact members do not become insulated fromeach other.

While it is preferable to employ tungsten or molybdenum as the cathodeand the other metal as the anode, the relations may in many cases bereversed with very satisfactory results, as, for instance, in the interrupter of ignition apparatus.

I claim as my invention:

1. A pair of cooperatin make-and-break contact members one of w ich iscomposed of a metal of the tungsten group and the other of which iscomposed of another metal.

2. A pair of cooperating make-and-break contact members the cathode ofwhich is composed of a metal of the tungsten group and the anode ofwhich is composed of another metal.

3. A pair of coiiperating make-and-break contact members one of which iscomposed of a metal of the tungsten group and the other of which iscomposed of a metal that does not become readily oxidized.

4. A pair of coo erating make-and-break contact members t e cathode ofwhich is composed of a metal of a tungsten group and the anode of whichis composed of a metal that does not become readily oxidized.

5. A pair of cooperating make-and-break contact members one of which iscomposed of metal of the tungsten group and the other of which iscomposed of a precious metal.

6. A pair of cooperating contact members one of which is composed ofsilver and the other of tungsten.

7. A air of cooperating contact members, the anode of which is composedof silver and the cathode of tun ten.

In testimony w ereof, I have hereunto subscribed my name this 31st dayof Dec., 1915.

HORACE V. s. TAYLOR.

